#include "main.h"

//function prototypes
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_I2C1_Init(void);
void errata_2_14_7_workaround(void);


int main(void)
{

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */

  LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_AFIO);
  LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_PWR);

  NVIC_SetPriorityGrouping(NVIC_PRIORITYGROUP_4);

  /** NOJTAG: JTAG-DP Disabled and SW-DP Enabled
  */
  LL_GPIO_AF_Remap_SWJ_NOJTAG();

  /* Configure the system clock */
  SystemClock_Config();

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_I2C1_Init();
  
  /* LED off */
  LL_GPIO_SetOutputPin(GPIOC, LL_GPIO_PIN_13);

  /* Start I2C Communication */
  errata_2_14_7_workaround();
  LL_I2C_GenerateStartCondition(I2C1);
  while(!LL_I2C_IsActiveFlag_SB(I2C1)){};
  (void) I2C1->SR1;   //read SR1 register

  LL_I2C_TransmitData8(I2C1, (0x27 << 1));      //0x27 is the address of the Slave
                                                //ARLO=1, MSL=0
  while(!LL_I2C_IsActiveFlag_ADDR(I2C1) && !LL_I2C_IsActiveFlag_AF(I2C1))
  {
  };  //the program hangs here

  LL_I2C_ClearFlag_ADDR(I2C1);
  LL_I2C_GenerateStopCondition(I2C1);


  /* Infinite loop---------------------------------------------------------------*/

  while (1)
  {
     /* if LED is blinking: I2C communication successful */
     LL_mDelay(250);
     LL_GPIO_TogglePin(GPIOC, LL_GPIO_PIN_13);
  }

}


void SystemClock_Config(void)
{
  LL_FLASH_SetLatency(LL_FLASH_LATENCY_2);
  while(LL_FLASH_GetLatency()!= LL_FLASH_LATENCY_2)
  {
  }
  LL_RCC_HSE_Enable();

   /* Wait till HSE is ready */
  while(LL_RCC_HSE_IsReady() != 1)
  {

  }
  LL_RCC_PLL_ConfigDomain_SYS(LL_RCC_PLLSOURCE_HSE_DIV_1, LL_RCC_PLL_MUL_8);
  LL_RCC_PLL_Enable();

   /* Wait till PLL is ready */
  while(LL_RCC_PLL_IsReady() != 1)
  {

  }
  LL_RCC_SetAHBPrescaler(LL_RCC_SYSCLK_DIV_1);
  LL_RCC_SetAPB1Prescaler(LL_RCC_APB1_DIV_16);
  LL_RCC_SetAPB2Prescaler(LL_RCC_APB2_DIV_16);
  LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_PLL);

   /* Wait till System clock is ready */
  while(LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_PLL)
  {

  }
  LL_Init1msTick(64000000);
  LL_SetSystemCoreClock(64000000);
}


static void MX_I2C1_Init(void)
{
  LL_I2C_InitTypeDef I2C_InitStruct = {0};

  LL_GPIO_InitTypeDef GPIO_InitStruct = {0};

  LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_GPIOB);

  /**I2C1 GPIO Configuration
  PB6   ------> I2C1_SCL
  PB7   ------> I2C1_SDA
  */
  GPIO_InitStruct.Pin = LL_GPIO_PIN_6|LL_GPIO_PIN_7;
  GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;
  GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_HIGH;
  GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_OPENDRAIN;
  LL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  /* Peripheral clock enable */
  LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_I2C1);

  /** I2C Initialization */
  LL_I2C_DisableOwnAddress2(I2C1);
  LL_I2C_DisableGeneralCall(I2C1);
  LL_I2C_EnableClockStretching(I2C1);
  I2C_InitStruct.PeripheralMode = LL_I2C_MODE_I2C;
  I2C_InitStruct.ClockSpeed = 100000;
  I2C_InitStruct.DutyCycle = LL_I2C_DUTYCYCLE_2;
  I2C_InitStruct.OwnAddress1 = 0;
  I2C_InitStruct.TypeAcknowledge = LL_I2C_ACK;
  I2C_InitStruct.OwnAddrSize = LL_I2C_OWNADDRESS1_7BIT;
  LL_I2C_Init(I2C1, &I2C_InitStruct);
  LL_I2C_SetOwnAddress2(I2C1, 0);
}


static void MX_GPIO_Init(void)
{
  LL_GPIO_InitTypeDef GPIO_InitStruct = {0};

  /* GPIO Ports Clock Enable */
  LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_GPIOC);
  LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_GPIOD);
  LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_GPIOA);
  LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_GPIOB);

  LL_GPIO_ResetOutputPin(GPIOC, LL_GPIO_PIN_13);

  GPIO_InitStruct.Pin = LL_GPIO_PIN_13;
  GPIO_InitStruct.Mode = LL_GPIO_MODE_OUTPUT;
  GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_LOW;
  GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;
  LL_GPIO_Init(GPIOC, &GPIO_InitStruct);

}


void errata_2_14_7_workaround(void)
{
  LL_I2C_Disable(I2C1);
  LL_GPIO_InitTypeDef GPIO_InitStruct = {0};

  GPIO_InitStruct.Pin = LL_GPIO_PIN_6|LL_GPIO_PIN_7;   //PIN_6 = SCL, PIN_7 = SDA
  GPIO_InitStruct.Mode = LL_GPIO_MODE_OUTPUT;
  GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_HIGH;
  GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_OPENDRAIN;
  LL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  LL_GPIO_SetOutputPin(GPIOB, LL_GPIO_PIN_6);
  LL_GPIO_SetOutputPin(GPIOB, LL_GPIO_PIN_7);
  while(!LL_GPIO_IsOutputPinSet(GPIOB, LL_GPIO_PIN_6) || !LL_GPIO_IsOutputPinSet(GPIOB, LL_GPIO_PIN_7)){}

  LL_GPIO_ResetOutputPin(GPIOB, LL_GPIO_PIN_7);
  while(LL_GPIO_IsOutputPinSet(GPIOB, LL_GPIO_PIN_7)){}

  LL_GPIO_ResetOutputPin(GPIOB, LL_GPIO_PIN_6);
  while(LL_GPIO_IsOutputPinSet(GPIOB, LL_GPIO_PIN_6)){}

  LL_GPIO_SetOutputPin(GPIOB, LL_GPIO_PIN_6);
  while(!LL_GPIO_IsOutputPinSet(GPIOB, LL_GPIO_PIN_6)){}

  LL_GPIO_SetOutputPin(GPIOB, LL_GPIO_PIN_7);
  while(!LL_GPIO_IsOutputPinSet(GPIOB, LL_GPIO_PIN_7)){}

  GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;
  GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_OPENDRAIN;
  LL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  LL_I2C_EnableReset(I2C1);
  LL_I2C_DisableReset(I2C1);

  LL_I2C_Enable(I2C1);
}